/*******************************************************************************
 * Filename:  target_core_fabric_lib.c
 *
 * This file contains generic high level protocol identifier and PR
 * handlers for TCM fabric modules
 *
 * Copyright (c) 2010 Rising Tide Systems, Inc.
 * Copyright (c) 2010 Linux-iSCSI.org
 *
 * Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/export.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>

#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_configfs.h>

#include "target_core_internal.h"
#include "target_core_pr.h"

/*
 * Handlers for Serial Attached SCSI (SAS)
 */
u8 sas_get_fabric_proto_ident(struct se_portal_group *se_tpg)
{
        /*
         * Return a SAS Serial SCSI Protocol identifier for loopback operations
         * This is defined in  section 7.5.1 Table 362 in spc4r17
         */
        return 0x6;
}
EXPORT_SYMBOL(sas_get_fabric_proto_ident);

u32 sas_get_pr_transport_id(
        struct se_portal_group *se_tpg,
        struct se_node_acl *se_nacl,
        struct t10_pr_registration *pr_reg,
        int *format_code,
        unsigned char *buf)
{
        unsigned char *ptr;
        int ret;

        /*
         * Set PROTOCOL IDENTIFIER to 6h for SAS
         */
        buf[0] = 0x06;
        /*
         * From spc4r17, 7.5.4.7 TransportID for initiator ports using SCSI
         * over SAS Serial SCSI Protocol
         */
        ptr = &se_nacl->initiatorname[4]; /* Skip over 'naa. prefix */

        ret = hex2bin(&buf[4], ptr, 8);
        if (ret < 0)
                pr_debug("sas transport_id: invalid hex string\n");

        /*
         * The SAS Transport ID is a hardcoded 24-byte length
         */
        return 24;
}
EXPORT_SYMBOL(sas_get_pr_transport_id);

u32 sas_get_pr_transport_id_len(
        struct se_portal_group *se_tpg,
        struct se_node_acl *se_nacl,
        struct t10_pr_registration *pr_reg,
        int *format_code)
{
        *format_code = 0;
        /*
         * From spc4r17, 7.5.4.7 TransportID for initiator ports using SCSI
         * over SAS Serial SCSI Protocol
         *
         * The SAS Transport ID is a hardcoded 24-byte length
         */
        return 24;
}
EXPORT_SYMBOL(sas_get_pr_transport_id_len);

/*
 * Used for handling SCSI fabric dependent TransportIDs in SPC-3 and above
 * Persistent Reservation SPEC_I_PT=1 and PROUT REGISTER_AND_MOVE operations.
 */
char *sas_parse_pr_out_transport_id(
        struct se_portal_group *se_tpg,
        const char *buf,
        u32 *out_tid_len,
        char **port_nexus_ptr)
{
        /*
         * Assume the FORMAT CODE 00b from spc4r17, 7.5.4.7 TransportID
         * for initiator ports using SCSI over SAS Serial SCSI Protocol
         *
         * The TransportID for a SAS Initiator Port is of fixed size of
         * 24 bytes, and SAS does not contain a I_T nexus identifier,
         * so we return the **port_nexus_ptr set to NULL.
         */
        *port_nexus_ptr = NULL;
        *out_tid_len = 24;

        return (char *)&buf[4];
}
EXPORT_SYMBOL(sas_parse_pr_out_transport_id);

/*
 * Handlers for Fibre Channel Protocol (FCP)
 */
u8 fc_get_fabric_proto_ident(struct se_portal_group *se_tpg)
{
        return 0x0;     /* 0 = fcp-2 per SPC4 section 7.5.1 */
}
EXPORT_SYMBOL(fc_get_fabric_proto_ident);

u32 fc_get_pr_transport_id_len(
        struct se_portal_group *se_tpg,
        struct se_node_acl *se_nacl,
        struct t10_pr_registration *pr_reg,
        int *format_code)
{
        *format_code = 0;
        /*
         * The FC Transport ID is a hardcoded 24-byte length
         */
        return 24;
}
EXPORT_SYMBOL(fc_get_pr_transport_id_len);

u32 fc_get_pr_transport_id(
        struct se_portal_group *se_tpg,
        struct se_node_acl *se_nacl,
        struct t10_pr_registration *pr_reg,
        int *format_code,
        unsigned char *buf)
{
        unsigned char *ptr;
        int i, ret;
        u32 off = 8;

        /*
         * PROTOCOL IDENTIFIER is 0h for FCP-2
         *
         * From spc4r17, 7.5.4.2 TransportID for initiator ports using
         * SCSI over Fibre Channel
         *
         * We convert the ASCII formatted N Port name into a binary
         * encoded TransportID.
         */
        ptr = &se_nacl->initiatorname[0];

        for (i = 0; i < 24; ) {
                if (!strncmp(&ptr[i], ":", 1)) {
                        i++;
                        continue;
                }
                ret = hex2bin(&buf[off++], &ptr[i], 1);
                if (ret < 0)
                        pr_debug("fc transport_id: invalid hex string\n");
                i += 2;
        }
        /*
         * The FC Transport ID is a hardcoded 24-byte length
         */
        return 24;
}
EXPORT_SYMBOL(fc_get_pr_transport_id);

char *fc_parse_pr_out_transport_id(
        struct se_portal_group *se_tpg,
        const char *buf,
        u32 *out_tid_len,
        char **port_nexus_ptr)
{
        /*
         * The TransportID for a FC N Port is of fixed size of
         * 24 bytes, and FC does not contain a I_T nexus identifier,
         * so we return the **port_nexus_ptr set to NULL.
         */
        *port_nexus_ptr = NULL;
        *out_tid_len = 24;

         return (char *)&buf[8];
}
EXPORT_SYMBOL(fc_parse_pr_out_transport_id);

/*
 * Handlers for Internet Small Computer Systems Interface (iSCSI)
 */

u8 iscsi_get_fabric_proto_ident(struct se_portal_group *se_tpg)
{
        /*
         * This value is defined for "Internet SCSI (iSCSI)"
         * in spc4r17 section 7.5.1 Table 362
         */
        return 0x5;
}
EXPORT_SYMBOL(iscsi_get_fabric_proto_ident);

u32 iscsi_get_pr_transport_id(
        struct se_portal_group *se_tpg,
        struct se_node_acl *se_nacl,
        struct t10_pr_registration *pr_reg,
        int *format_code,
        unsigned char *buf)
{
        u32 off = 4, padding = 0;
        u16 len = 0;

        spin_lock_irq(&se_nacl->nacl_sess_lock);
        /*
         * Set PROTOCOL IDENTIFIER to 5h for iSCSI
        */
        buf[0] = 0x05;
        /*
         * From spc4r17 Section 7.5.4.6: TransportID for initiator
         * ports using SCSI over iSCSI.
         *
         * The null-terminated, null-padded (see 4.4.2) ISCSI NAME field
         * shall contain the iSCSI name of an iSCSI initiator node (see
         * RFC 3720). The first ISCSI NAME field byte containing an ASCII
         * null character terminates the ISCSI NAME field without regard for
         * the specified length of the iSCSI TransportID or the contents of
         * the ADDITIONAL LENGTH field.
         */
        len = sprintf(&buf[off], "%s", se_nacl->initiatorname);
        /*
         * Add Extra byte for NULL terminator
         */
        len++;
        /*
         * If there is ISID present with the registration and *format code == 1
         * 1, use iSCSI Initiator port TransportID format.
         *
         * Otherwise use iSCSI Initiator device TransportID format that
         * does not contain the ASCII encoded iSCSI Initiator iSID value
         * provied by the iSCSi Initiator during the iSCSI login process.
         */
        if ((*format_code == 1) && (pr_reg->isid_present_at_reg)) {
                /*
                 * Set FORMAT CODE 01b for iSCSI Initiator port TransportID
                 * format.
                 */
                buf[0] |= 0x40;
                /*
                 * From spc4r17 Section 7.5.4.6: TransportID for initiator
                 * ports using SCSI over iSCSI.  Table 390
                 *
                 * The SEPARATOR field shall contain the five ASCII
                 * characters ",i,0x".
                 *
                 * The null-terminated, null-padded ISCSI INITIATOR SESSION ID
                 * field shall contain the iSCSI initiator session identifier
                 * (see RFC 3720) in the form of ASCII characters that are the
                 * hexadecimal digits converted from the binary iSCSI initiator
                 * session identifier value. The first ISCSI INITIATOR SESSION
                 * ID field byte containing an ASCII null character
                 */
                buf[off+len] = 0x2c; off++; /* ASCII Character: "," */
                buf[off+len] = 0x69; off++; /* ASCII Character: "i" */
                buf[off+len] = 0x2c; off++; /* ASCII Character: "," */
                buf[off+len] = 0x30; off++; /* ASCII Character: "0" */
                buf[off+len] = 0x78; off++; /* ASCII Character: "x" */
                len += 5;
                buf[off+len] = pr_reg->pr_reg_isid[0]; off++;
                buf[off+len] = pr_reg->pr_reg_isid[1]; off++;
                buf[off+len] = pr_reg->pr_reg_isid[2]; off++;
                buf[off+len] = pr_reg->pr_reg_isid[3]; off++;
                buf[off+len] = pr_reg->pr_reg_isid[4]; off++;
                buf[off+len] = pr_reg->pr_reg_isid[5]; off++;
                buf[off+len] = '\0'; off++;
                len += 7;
        }
        spin_unlock_irq(&se_nacl->nacl_sess_lock);
        /*
         * The ADDITIONAL LENGTH field specifies the number of bytes that follow
         * in the TransportID. The additional length shall be at least 20 and
         * shall be a multiple of four.
        */
        padding = ((-len) & 3);
        if (padding != 0)
                len += padding;

        buf[2] = ((len >> 8) & 0xff);
        buf[3] = (len & 0xff);
        /*
         * Increment value for total payload + header length for
         * full status descriptor
         */
        len += 4;

        return len;
}
EXPORT_SYMBOL(iscsi_get_pr_transport_id);

u32 iscsi_get_pr_transport_id_len(
        struct se_portal_group *se_tpg,
        struct se_node_acl *se_nacl,
        struct t10_pr_registration *pr_reg,
        int *format_code)
{
        u32 len = 0, padding = 0;

        spin_lock_irq(&se_nacl->nacl_sess_lock);
        len = strlen(se_nacl->initiatorname);
        /*
         * Add extra byte for NULL terminator
         */
        len++;
        /*
         * If there is ISID present with the registration, use format code:
         * 01b: iSCSI Initiator port TransportID format
         *
         * If there is not an active iSCSI session, use format code:
         * 00b: iSCSI Initiator device TransportID format
         */
        if (pr_reg->isid_present_at_reg) {
                len += 5; /* For ",i,0x" ASCII seperator */
                len += 7; /* For iSCSI Initiator Session ID + Null terminator */
                *format_code = 1;
        } else
                *format_code = 0;
        spin_unlock_irq(&se_nacl->nacl_sess_lock);
        /*
         * The ADDITIONAL LENGTH field specifies the number of bytes that follow
         * in the TransportID. The additional length shall be at least 20 and
         * shall be a multiple of four.
         */
        padding = ((-len) & 3);
        if (padding != 0)
                len += padding;
        /*
         * Increment value for total payload + header length for
         * full status descriptor
         */
        len += 4;

        return len;
}
EXPORT_SYMBOL(iscsi_get_pr_transport_id_len);

char *iscsi_parse_pr_out_transport_id(
        struct se_portal_group *se_tpg,
        const char *buf,
        u32 *out_tid_len,
        char **port_nexus_ptr)
{
        char *p;
        u32 tid_len, padding;
        int i;
        u16 add_len;
        u8 format_code = (buf[0] & 0xc0);
        /*
         * Check for FORMAT CODE 00b or 01b from spc4r17, section 7.5.4.6:
         *
         *       TransportID for initiator ports using SCSI over iSCSI,
         *       from Table 388 -- iSCSI TransportID formats.
         *
         *    00b     Initiator port is identified using the world wide unique
         *            SCSI device name of the iSCSI initiator
         *            device containing the initiator port (see table 389).
         *    01b     Initiator port is identified using the world wide unique
         *            initiator port identifier (see table 390).10b to 11b
         *            Reserved
         */
        if ((format_code != 0x00) && (format_code != 0x40)) {
                pr_err("Illegal format code: 0x%02x for iSCSI"
                        " Initiator Transport ID\n", format_code);
                return NULL;
        }
        /*
         * If the caller wants the TransportID Length, we set that value for the
         * entire iSCSI Tarnsport ID now.
         */
         if (out_tid_len != NULL) {
                add_len = ((buf[2] >> 8) & 0xff);
                add_len |= (buf[3] & 0xff);

                tid_len = strlen(&buf[4]);
                tid_len += 4; /* Add four bytes for iSCSI Transport ID header */
                tid_len += 1; /* Add one byte for NULL terminator */
                padding = ((-tid_len) & 3);
                if (padding != 0)
                        tid_len += padding;

                if ((add_len + 4) != tid_len) {
                        pr_debug("LIO-Target Extracted add_len: %hu "
                                "does not match calculated tid_len: %u,"
                                " using tid_len instead\n", add_len+4, tid_len);
                        *out_tid_len = tid_len;
                } else
                        *out_tid_len = (add_len + 4);
        }
        /*
         * Check for ',i,0x' seperator between iSCSI Name and iSCSI Initiator
         * Session ID as defined in Table 390 - iSCSI initiator port TransportID
         * format.
         */
        if (format_code == 0x40) {
                p = strstr(&buf[4], ",i,0x");
                if (!p) {
                        pr_err("Unable to locate \",i,0x\" seperator"
                                " for Initiator port identifier: %s\n",
                                &buf[4]);
                        return NULL;
                }
                *p = '\0'; /* Terminate iSCSI Name */
                p += 5; /* Skip over ",i,0x" seperator */

                *port_nexus_ptr = p;
                /*
                 * Go ahead and do the lower case conversion of the received
                 * 12 ASCII characters representing the ISID in the TransportID
                 * for comparison against the running iSCSI session's ISID from
                 * iscsi_target.c:lio_sess_get_initiator_sid()
                 */
                for (i = 0; i < 12; i++) {
                        if (isdigit(*p)) {
                                p++;
                                continue;
                        }
                        *p = tolower(*p);
                        p++;
                }
        }

        return (char *)&buf[4];
}
EXPORT_SYMBOL(iscsi_parse_pr_out_transport_id);